Low Industrialized Recycled Plastic Connectors for Sustainable Bamboo Structures

The paper presents an innovative approach to producing structural connectors for bamboo constructions using recycled plastic. This solution enhances the sustainability of bamboo structures while simultaneously promoting the valorization of plastics waste. The aim is to conduct a preliminary investigation in the possible use of high-density polyethylene (HDPE) as a structural material. Two connectors’ geometries have been developed, both specifically devised for bamboo truss systems: a paddle-shaped design and an oval-shaped design. In both designs, a series of circularly arranged holes enables flexible orientation of the connected elements. The connectors are fabricated melting layers of rough-milled HDPE, sourced from waste materials, which are cast in a mold incorporating an agave braid as a reinforcement. The manufacturing process is intentionally low-tech and accessible, relying only on basic tools and equipment for milling, melting, and casting. This approach makes the proposed connectors particularly suitable for adoption in developing countries. To assess their performance, physical and mechanical tests were conducted on the base material, evaluating density, void content, and tensile strength. The tensile strength of the finished connectors results in an average value of 12.73 MPa, with a standard deviation of 2.34 MPa and a coefficient of variation CV of 18.4%, consistent with the results of tests reported in the literature. Although the sample size is limited, the obtained data are sufficient to assess the feasibility of the proposed solution, demonstrating a reasonable reliability of both the molding process and the mechanical performance of the connector.